UNIVERSITY  OF   CALIFORNIA   PUBLICATIONS 

COLLEGE  OF  AGRICULTURE 
AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,  CALIFORNIA 


STORAGE  OF  PERISHABLE  FRUITS 
AT  FREEZING  TEMPERATURES 


PRELIMINARY   REPORT 

BY 

W.  V.  CRUESS,  E.  L.  OVERHOLSER  and  S.  A.  BJARNASON 


BULLETIN  No.  324 

August.  1920 


UNIVERSITY   OF  CALIFORNIA   PRESS 

BERKELEY 

1920 


David  P.  Barrows,  President  of  the  University. 


EXPERIMENT  STATION  STAFF 

HEADS  OF  DIVISIONS 

Thomas  Forsyth  Hunt,  Dean. 

Edward  J.  Wickson,  Horticulture  (Emeritus). 

Walter  Mulford,  Forestry,  Director  of  Resident  Instruction. 

C.  M.  Haring,  Veterinary  Science,  Director  Agricultural  Experiment  Station. 

B.  H.  Crocheron,  Director  of  Agricultural  Extension. 
Hubert  E.  Van  Norman,  Vice-Director;  Dairy  Management. 

James  T.  Barrett,  Acting  Director  of  Citrus  Experiment  Station;  Plant  Pathology 
William  A.  Setchell,  Botany. 
Myer  E.  Jaffa  Nutrition. 
Charles  W.  Woodworth,  Entomology. 
Ralph  E.  Smith,  Plant  Pathology. 
J.  Eliot  Coit,  Citriculture. 
John  W.  Gilmore,  Agronomy. 
Charles  F.  Shaw,  Soil  Technology. 
John  W.  Gregg,  Landscape  Gardening  and  Floriculture. 
Frederic  T.  Bioletti,  Viticulture  and  Fruit  Products. 
Warren  T.  Clarke,  Agricultural  Extension. 
John  S.  Burd,  Agricultural  Chemistry. 
Charles  B.  Lipman,  Soil  Chemistry  and  Bacteriology. 
Ernest  B.  Babcock,  Genetics. 
Gordon  H.  True,  Animal  Husbandry. 
Fritz  W.  Woll,  Animal  Nutrition. 
W.  P.  Kelley,  Agricultural  Chemistry. 
H.  J.  Quayle,  Entomology. 
Elwood  Mead,  Rural  Institutions. 
H.  S.  Reed,  Plant  Physiology. 
L.  D.  Batchelor,  Orchard  Management. 
J.  C.  Whitten,  Pomology, 
f Frank  Adams,  Irrigation  Investigations. 

C.  L.  Roadhouse,  Dairy  Industry. 
R.  L.  Adams,  Farm  Management. 

F.  L.  Griffin,  Agricultural  Education. 
John  E.  Dougherty,  Poultry  Husbandry. 
L.  J.  Fletcher,  Agricultural  Engineering. 
Edwin  C.  Voorhies,  Assistant  to  the  Dean. 

fin  co-operation  with  office  of  Public  Roads  and  Rural  Engineering,  U.  S.  Department  of  Agriculture. 


STORAGE  OF  PERISHABLE  FRUITS 
AT  FREEZING  TEMPERATURES 

Preliminary  Eeport  by 
W.  V.  GRUESS,  E.  L.  OVERHOLSER,  and  S.  A.  BJARNASON 


INTRODUCTION 

Many  quickly  perishable  fruits  such  as  berries,  apricots,  cherries 
and  others  can  not  be  held  successfully  for  very  long  periods  at  the 
usual  cold  storage  temperatures  for  fruit,  of  32°  F.  to  35°  F.  because 
of  rapid  softening  and  decay.  If  held  without  preliminary  treatment 
at  a  temperature  of  10°  F.,  low  enough  to  freeze  the  fruit,  there  is  a 
tendency  in  certain  fruits  for  the  color  to  become  brown  and  the  flavor 
seriously  impaired.  It,  therefore,  seemed  desirable  to  make  a  pre- 
liminary experimental  study  of  methods  of  treating  the  above  fruits 
before  storage,  at  10°  F.  to  prevent  or  minimize  undesirable  changes 
in  color  and  flavor.  At  these  low  temperatures  molding  or  fermenta- 
tion does  not  occur  and  ripening  processes  are  effectively  arrested. 
Therefore,  if  the  problems  of  retention  of  color  and  retention  of  flavor 
could  be  satisfactorily  solved,  this  method  of  storage  should  have  wide 
application. 

The  investigations  have  included  not  only  experiments  upon  the 
storage  of  various  quickly  perishable  fruits,  but  also  upon  the  utiliza- 
tion of  such  fruit  in  canning,  preserving,  confections,  etc.,  after  six 
to  ten  months  storage. 

The  data  of  the  first  year's  experiments  have  been  so  promising 
that  it  is  believed  the  results  will  be  of  considerable  immediate  value 
to  cold  storage  establishments,  ice  cream  manufacturers,  fruit  pre- 
serving factories,  and  others.  Former  breweries  are  equipped  with 
large  refrigerating  plants,  very  large  glass  lined  or  wooden  tank  cold 
storage  capacity,  and  other  facilities  which  could  be  used  for  the 
receiving,  preparation  and  storage  of  the  types  of  fruits  used  in  the 
tests.  It  is  probable  that  a  very  extensive  market  could  be  quickly 
developed  for  such  fruits  during  the  winter  and  early  spring  months 
and  it  is  believed  that  the  development  of  such  an  industry  offers  a 
very  attractive  field. 

REVIEW    OF    PREVIOUS    WORK 

The  extensive  keeping  of  such  quickly  perishable  fruits  under 
refrigeration  is  a  comparatively  new  undertaking.  A  few  storage 
houses  have  adopted  certain  methods  for  particular  fruits  which 
enable  them  to  keep  the  product  for  a  considerable  period  of  time 


26  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

by  employing  freezing  temperatures.  Usually  different  methods  are 
employed  by  the  different  houses.  As  a  rule,  they  have  simply  found 
satisfactory  methods  and  have  not  definitely  determined  that  these 
are  the  best. 

Fulton1  in  1907  mentioned  that  in  certain  of  the  larger  cities  the 
practice  of  freezing  small  fruits  for  the  purpose  of  holding  them 
indefinitely  in  a  frozen  condition  to  be  used  in  making  ice  cream  and 
pastries  had  come  into  use  to  a  limited  extent  among  confectioners, 
bakers  and  restauranteurs.  He  pointed  out  that  much  of  the  fruit 
used  for  this  purpose  was  bought  when  the  market  price  was  low,  such 
as  on  Saturday  evenings  or  when  the  market  was  glutted.  The  fruit 
was  hurried  into  cold  storage  and  frozen  at  a  temperature  ranging 
from  about  5°  F.  to  12°  F.  Previously  some  restauranteurs  had 
packed  berries  in  dry  granulated  sugar  and  held  them  at  a  tempera- 
ture of  31°  F.  to  32°  F.,  but  this  practice  has  been  discarded  and  the 
freezing  method  adopted. 

Fulton  gives  further  information  based  primarily  upon  observa- 
tions, stating  that  frozen  strawberries  for  ice  cream  have  been  used 
in  a  limited  way  by  confectioners,  while  frozen  blackberries,  currants, 
blackcap  raspberries,  huckleberries,  and  other  small  fruits  were  being 
used  successfully  for  pies  and  other  pastries  by  a  few  restauranteurs 
and  bakers.  He  cites  the  hearsay  that  when  made  into  pies  the  flavor 
of  the  product  was  said  to  be  practically  equal  to  that  made  of  fresh 
fruit.  Considerable  quantities  of  cherries  and  damson  plums  were 
also  frozen  by  one  company  for  use  in  pies.  Usually  these  latter 
fruits  were  put  into  the  pies  whole  without  seeding.  Sometimes, 
however,  they  were  dipped  into  cold  water  to  take  out  the  frost  and 
then  pitted.  The  fact  was  noted  that  frozen  cherries  and  plums 
shriveled  somewhat  in  baking,  and  were  therefore  not  used  so  suc- 
cessfully as  some  of  the  berries. 

Fulton  also  mentions  two  tests  made  by  the  Bureau  of  Plant 
Industry.  In  one  test  Gandy  strawberries  were  frozen  and  held 
at  a  temperature  of  10°  F.  to  14°  F.  for  ten  months  in  tight  paper 
wrapped  cartons  of  paraffined  cardboard,  with  very  little  change  in 
color  and  practically  no  shrinkage.  Berries  frozen  in  open  crates 
at  the  same  time  evaporated  and  shrunk  away  fully  one-half  within 
a  few  months.  Fulton's  advice  was  that  if  the  fruit  was  intended 
for  long  preservation,  it  should  be  placed  in  loosely  covered  tin  cans 
to  prevent  evaporation,  but  if  it  was  to  be  kept  only  a  short  time, 
it  could  be  stored  in  the  ordinary  crates  in  which  it  was  conveyed  to 
market. 


i  S.  H.  Fulton,  The  Cold  Storage  of  Small  Fruits,  Bur.  Plant  Ind.,  Bull.  No. 
108,  U.  S.  D.  A.,  1907. 


Bulletin  324  STORAGE  OF  PERISHABLE  FRUITS  27 

In  the  other  test  Gandy  and  Tennessee  varieties  of  strawberries 
and  Miller  and  Kansas  raspberries  were  frozen  and  stored  in  different 
styles  of  packages  at  a  temperature  of  12°  F.  in  a  general  freezing 
room  containing  meats,  poultry,  and  game.  The  packages  used  were  (1) 
paper-wrapped  paraffined  cardboard  carton;  (2)  the  same  carton  with 
an  additional  heavy  paraffined  paper  wrap  over  the  cardboard,  which 
with  the  outside  paper  jacket  constituted  a  triple  thick  carton;  and 
(3)  the  common  open  slat  crate  generally  used.  After  approximate^ 
seven  months,  the  fruit  was  still  normal  in  appearance  except  for  a 
slight  fading  in  the  color  of  the  strawberries  and  a  slight  shrinkage 
of  both  strawberries  and  raspberries  in  the  open  crates.  The  fruit 
in  the  closed  packages  was  plump  and  attractive  in  appearance.  The 
flavor  of  the  fruit  of  both  strawberries  and  raspberries  in  the  open 
crates  was  objectionable  since  apparently  the  fruit  had  absorbed 
odors  from  other  commodities  in  the  storage  room.  The  flavor  of  the 
fruit  in  the  triple  box  was  a  little  better,  but  Fulton  believed  it  had 
been  "tainted"  through  the  effect  of  the  carbon-dioxide  gas  exhaled 
by  the  fruit  before  it  was  solidified  in  freezing.  The  flavor  of  the 
fruit  in  the  double  carton  which  was  not  so  impervious  to  the  air,  was 
not  contaminated,  and  it  retained  much  of  the  sprightliness  and  flavor 
of  the  fresh  fruit.  In  Fulton's  judgment  this  test  seemed  to  indicate 
that  for  frozen  fruit,  the  best  results  can  be  obtained  by  the  use  of^a 
closed  package  provided  the  package  is  not  so  tight  as  to  prevent  the 
escape  of  the  gases  given  off  by  the  fruit  after  it  is  packed  and  before 
it  is  frozen. 

Darrow2  writes  of  two  methods  of  preserving  strawberries  in  cold 
storage  which  seem  to  be  practices  followed  by  a  few  cold  storage 
houses.  The  first  method  is  suggested  as  being  adapted  for  packing- 
small  quantities  of  strawberries  for  use  when  not  in  season,  with  the 
preservation  of  the  fresh-fruit  flavor.  Sound,  ripe  berries  are  selected, 
washed  and  hulled.  A  tin  of  convenient  size  to  which  a  tight  cover 
can  be  fitted  is  used.  To  each  ten  pounds  of  fruit  one  cup  of  sugar 
is  added.  The  cans  are  filled  with  sugar  and  berries,  the  tops  are 
fitted  on  and  their  edges  covered  with  the  adhesive  tape  used  in 
sealing  packages.  The  containers  of  fruit  are  then  put  in  freezing 
cold  storage  and  kept  frozen  until  wanted.  Darrow  describes  this 
product  as  being  satisfactory  when  used  for  short-cakes,  by  restau- 
rants and  hotels,  and  as  crushed  fruit  at  soda  fountains,  and  by  ice 
cream  manufacturers. 

The  second  method  outlined  is  referred  to  as  being  the  one 
employed  by  the  large  manufacturers  of  the  crushed  fruits  and  syrups 

2  George  W.  Darrow,  Strawberry  Culture,  Western  United  States  Farmers ' 
Bulletin  1027,  U.  S.  D.  A.,  1919. 


26  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

by  employing  freezing  temperatures.  Usually  different  methods  are 
employed  by  the  different  houses.  As  a  rule,  they  have  simply  found 
satisfactory  methods  and  have  not  definitely  determined  that  these 
are  the  best. 

Fulton1  in  1907  mentioned  that  in  certain  of  the  larger  cities  the 
practice  of  freezing  small  fruits  for  the  purpose  of  holding  them 
indefinitely  in  a  frozen  condition  to  be  used  in  making  ice  cream  and 
pastries  had  come  into  use  to  a  limited  extent  among  confectioners, 
bakers  and  restauranteurs.  He  pointed  out  that  much  of  the  fruit 
used  for  this  purpose  was  bought  when  the  market  price  was  low,  such 
as  on  Saturday  evenings  or  when  the  market  was  glutted.  The  fruit 
was  hurried  into  cold  storage  and  frozen  at  a  temperature  ranging 
from  about  5°  F.  to  12°  F.  Previously  some  restauranteurs  had 
packed  berries  in  dry  granulated  sugar  and  held  them  at  a  tempera- 
ture of  31°  F.  to  32°  F.,  but  this  practice  has  been  discarded  and  the 
freezing  method  adopted. 

Fulton  gives  further  information  based  primarily  upon  observa- 
tions, stating  that  frozen  strawberries  for  ice  cream  have  been  used 
in  a  limited  way  by  confectioners,  while  frozen  blackberries,  currants, 
blackcap  raspberries,  huckleberries,  and  other  small  fruits  were  being 
used  successfully  for  pies  and  other  pastries  by  a  few  restauranteurs 
and  bakers.  He  cites  the  hearsay  that  when  made  into  pies  the  flavor 
of  the  product  was  said  to  be  practically  equal  to  that  made  of  fresh 
fruit.  Considerable  quantities  of  cherries  and  damson  plums  were 
also  frozen  by  one  company  for  use  in  pies.  Usually  these  latter 
fruits  were  put  into  the  pies  whole  without  seeding.  Sometimes, 
however,  they  were  dipped  into  cold  water  to  take  out  the  frost  and 
then  pitted.  The  fact  was  noted  that  frozen  cherries  and  plums 
shriveled  somewhat  in  baking,  and  were  therefore  not  used  so  suc- 
cessfully as  some  of  the  berries. 

Fulton  also  mentions  two  tests  made  by  the  Bureau  of  Plant 
Industry.  In  one  test  Gandy  strawberries  were  frozen  and  held 
at  a  temperature  of  10°  F.  to  14°  F.  for  ten  months  in  tight  paper 
wrapped  cartons  of  paraffined  cardboard,  with  very  little  change  in 
color  and  practically  no  shrinkage.  Berries  frozen  in  open  crates 
at  the  same  time  evaporated  and  shrunk  away  fully  one-half  within 
a  few  months.  Fulton's  advice  was  that  if  the  fruit  was  intended 
for  long  preservation,  it  should  be  placed  in  loosely  covered  tin  cans 
to  prevent  evaporation,  but  if  it  was  to  be  kept  only  a  short  time, 
it  could  be  stored  in  the  ordinary  crates  in  which  it  was  conveyed  to 
market. 


i  S.  H.  Fulton,  The  Cold  Storage  of  Small  Fruits,  Bur.  Plant  Ind.,  Bull.  No. 
108,  U.  S.  D.  A.,  1907. 


Bulletin  324  STORAGE    OF   PERISHABLE   FRUITS  27 

In  the  other  test  Gandy  and  Tennessee  varieties  of  strawberries 
and  Miller  and  Kansas  raspberries  were  frozen  and  stored  in  different 
styles  of  packages  at  a  temperature  of  12°  F.  in  a  general  freezing 
room  containing  meats,  poultry,  and  game.  The  packages  used  were  (1) 
paper-wrapped  paraffined  cardboard  carton;  (2)  the  same  carton  with 
an  additional  heavy  paraffined  paper  wrap  over  the  cardboard,  which 
with  the  outside  paper  jacket  constituted  a  triple  thick  carton;  and 
(3)  the  common  open  slat  crate  generally  used.  After  approximately 
seven  months,  the  fruit  was  still  normal  in  appearance  except  for  a 
slight  fading  in  the  color  of  the  strawberries  and  a  slight  shrinkage 
of  both  strawberries  and  raspberries  in  the  open  crates.  The  fruit 
in  the  closed  packages  was  plump  and  attractive  in  appearance.  The 
flavor  of  the  fruit  of  both  strawberries  and  raspberries  in  the  open 
crates  was  objectionable  since  apparently  the  fruit  had  absorbed 
odors  from  other  commodities  in  the  storage  room.  The  flavor  of  the 
fruit  in  the  triple  box  was  a  little  better,  but  Fulton  believed  it  had 
been  "tainted"  through  the  effect  of  the  carbon-dioxide  gas  exhaled 
by  the  fruit  before  it  was  solidified  in  freezing.  The  flavor  of  the 
fruit  in  the  double  carton  which  was  not  so  impervious  to  the  air,  was 
not  contaminated,  and  it  retained  much  of  the  sprightliness  and  flavor 
of  the  fresh  fruit.  In  Fulton's  judgment  this  test  seemed  to  indicate 
that  for  frozen  fruit,  the  best  results  can  be  obtained  by  the  use  of#a 
closed  package  provided  the  package  is  not  so  tight  as  to  prevent  the 
escape  of  the  gases  given  off  by  the  fruit  after  it  is  packed  and  before 
it  is  frozen. 

Darrow2  writes  of  two  methods  of  preserving  strawberries  in  cold 
storage  which  seem  to  be  practices  followed  by  a  few  cold  storage 
houses.  The  first  method  is  suggested  as  being  adapted  for  packing 
small  quantities  of  strawberries  for  use  when  not  in  season,  with  the 
preservation  of  the  fresh-fruit  flavor.  Sound,  ripe  berries  are  selected, 
washed  and  hulled.  A  tin  of  convenient  size  to  which  a  tight  cover 
can  be  fitted  is  used.  To  each  ten  pounds  of  fruit  one  cup  of  sugar 
is  added.  The  cans  are  filled  with  sugar  and  berries,  the  tops  are 
fitted  on  and  their  edges  covered  with  the  adhesive  tape  used  in 
sealing  packages.  The  containers  of  fruit  are  then  put  in  freezing 
cold  storage  and  kept  frozen  until  wanted.  Darrow  describes  this 
product  as  being  satisfactory  when  used  for  short-cakes,  by  restau- 
rants and  hotels,  and  as  crushed  fruit  at  soda  fountains,  and  by  ice 
cream  manufacturers. 

The  second  method  outlined  is  referred  to  as  being  the  one 
employed  by  the  large  manufacturers  of  the  crushed  fruits  and  syrups 

2  George  W.  Darrow,  Strawberry  Culture,  Western  United  States  Farmers ' 
Bulletin  1027,  U.  S.  D.  A.,  1919. 


28  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

used  by  the  soda  fountain  and  ice  cream  trade  in  the  preparation  of 
their  product.  The  uncooked  berries  are  kept  in  barrels  in  cold 
storage,  preserved  in  the  following  manner:  the  strawberries  are 
hulled,  sorted  and  then  washed.  The  washing  is  done  by  running  the 
berries  on  a  belt  through  a  tank  of  water.  They  are  then  conveyed 
over  another  belt,  where  they  are  slowly  turned  and  sprayed  with 
water.  After  the  washing,  the  berries  drop  into  pans  and  are  weighed. 
From  one-half  to  one  pound  of  sugar  is  added  to  each  pound  of 
berries,  proportions  used  depending  upon  the  variety,  the  ripeness 
of  the  fruit,  the  moisture  conditions,  and  the  way  in  which  the  product 
is  to  be  used.  The  proportions  most  commonly  used  are  one-half 
pound  of  sugar  to  one  pound  of  fruit. 

Heavy  water-tight  barrels  holding  about  375  pounds  of  the  mixture 
of  berries  and  sugar  are  used.  Before  use  they  are  carefully  cleaned 
and  coated  on  the  inside  with  parafine,  which  is  applied  hot  with  a 
paint-brush.  The  sugar  and  berries  are  put  in  alternate  layers  and 
mixed  by  a  machine  or  by  hand.  As  soon  as  the  barrels  are  headed 
they  are  shipped  in  a  refrigerator  car  to  a  cold  storage  warehouse, 
where  they  are  held  at  a  temperature  of  30°  F.  or  lower.  Several 
thousand  barrels  of  strawberries  are  put  up  in  this  manner  each  year. 

Darrow  writes  that  if  equal  weights  of  sugar  and  berries  are  used, 
tlje  barrels  of  fruit  may  be  stored  at  a  temperature  of  34°  F.  to  36°  F., 
but  if  the  fruit  is  to  be  held  for  long  periods  the  flavor  is  best  pre- 
served at  a  lower  temperature. 

EFFECT    OF    PRELIMINARY    TREATMENT3 

The  experiments  reported  in  'this  publication  have  been  divided 
into  two  groups,  namely  "Effect  of  Preliminary  Treatment"  and 
"Utilization  of  Fruits  from  Freezing  Storage." 

During  the  summer  of  1919,  strawberries,  loganberries  and  red 
raspberries,  currants,  Royal  Anne  cherries  and  Royal  Apricots  were 
received  at  the  University.  With  the  exception  of  the  apricots,  which 
came  from  the  University  Farm  at  Davis,  the  fruits  were  purchased 
from  local  commission  houses.  The  cherries  were  grown  in  Oregon; 
the  other  fruits  were  California-grown  products.  The  fruits  were 
prepared  in  the  Fruit  Products  Laboratory  for  storage.  In  most 
cases  stoneware  crocks  were  used  as  containers.  The  fruit  was  then 
placed  in  rooms  of  the  cold  storage  plant  of  the  Division  of  Pomology. 
Temperatures  of  32°  F.  and  10°  F.  were  compared  and  small  lots 
of  the  fresh  fruits  were  made  into  preserves  and  stored  in  glass  jars 

3  The  authors  wish  to  thank  Mr.  A.  W.  Christie,  Instructor  in  Fruit  Products, 
for  suggestions  and  assistance  given  during  preparation  of  the  fruit  for  storage. 


Bulletin  324 


STORAGE    OF    PERISHABLE    FRUITS 


29 


at  room  temperature  to  serve  as  checks  for  the  various  lots  held  in 
cold  storage. 

The    following    tables    and    observations    summarize    the    results 
obtained. 

Table  1. — Cherries 


Stored  at  8°  F.  to  12°  F 

Date  stored,  June  23,  191.9. 

Expt. 
No. 

Treatment 
before  storing 

Notes  on 
August  2,  1919 

Samples  taken  out  and 
thawed  on  January  23,  1920 

Date 
spoiled 

Color 

Flavor 

Texture 

at  room 
temperature 

15 

Whole     cherries, 
no  treatment 

Brown  color 

Dark 
brown 

Good  to 
fair 

Medium 

January 
27th. 

5 

Pitted  cherries 

Brown  color 

Dark 
brown 

Good  to 
fair 

Medium 

January 
27th. 

1 

Pitted,  frozen  in 
water 

Color  not  chang- 
ed 

Very 
good, 
natural 

Excellent 

Good 

January 
29th. 

2 

Pitted,  frozen  in 
10%  sugar 
solution 

Color  not  chang- 
ed 

Very- 
good, 
natural 

Excellent 

Good 

January 
29th. 

3 

Pitted,  frozen  in 
20%  sugar 
solution 

Color  not  chang- 
ed 

Very 
good, 
natural 

Excellent 

Good 

January 
29th 

4 

Pitted,  frozen  in 
40%  sugar 
solution 

Color  not  chang- 
ed 

Very 
good, 
natural 

Excellent 

Good 

January 
29th. 

7 

Same   as   No.    1 
but  heated  to 
175°  F.  before 
storage 

Color  pinkish 

Bleached 
to  grey- 
ish pink 

Very 
good 

Medium 
to  poor 

January 
27th. 

8 

Same  as  No.  2, 
but  heated  to 
175°  F.  before 
storage 

Color  pinkish, 
color  and  flavor 
gone  into  juice  to 
some  extent 

Bleached 
to  grey- 
ish pink 

Very 

good 

Medium 
to  poor 

January 
27th. 

9 

Same  as  No.  3, 
but  heated  to 
175°  F.  before 
storage 

Color  pinkish, 
color  and  flavor 
gone  into  juice  to 
some  extent 

Bleached 
to  grey- 
ish pink 

Very 
good 

Medium 
to  poor 

January 
27th. 

10 

Same  as  No.  4, 
but  heated  to 
175°  F.  before 
storage 

Color  pinkish, 
color  and  flavor 
gone  into  juice  to 
some  extent 

Bleached 
to  grey- 
ish pink 

Very 
good 

Medium 
to  poor 

January 
28th. 

11 

Same  as  No.   1, 
but  heated  to 
212°  F.  before 
storage 

Color  bleached 

Bleached 
to  grey- 
ish pink 
or  light 
gray 

Good 

Poor 

January 
27th. 

12 

Same  as  No.  2, 
but  heated  to 
212°  F.  before 
storage 

Color  bleached 

Bleached 
to  grey- 
ish pink 
or  light 
gray 

Good 

Poor 

January 
27th. 

30  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Table  1  — Cherries — {Continued) 


Expt. 

Treatment 
before  storing 

Notes  on 
August  2,  1919 

Samples  taken  out  and 
thawed  on  January  23,  1920 

Date 
spoiled 

No. 

Color 

Flavor 

Texture 

at  room 
temperature 

13 

Same  as  No.  3, 
but  heated  to 
212°  F.  before 
storage 

Color  bleached 

Bleached 
to  grey- 
ish pink 
or  light 
gray 

Good 

Poor 

January 
27th. 

14 

Same  as  No.  4, 
but  heated  to 
212°  F.  before 
storage 

Color  bleached 

Good 

Poor 

January 
29th. 

18 

Same  as  No.  11, 
but  heated  to 
212°  F.  20min. 
before  storage 

At   Room   Tem- 
^[perature: 

Color  bleached 

Bleached 

Good 

Flavor  of 
cherry  in 
juice 

6 

Cherries  in  water 
with  sulfurous 
acid 

At  32  F.: 

Bleached 
white 

Flavor- 
less 

Tough 

16 

Whole  cherries 

Spoiled  before 
August  2d. 

Bulletin  324 


STORAGE  OF  PERISHABLE  FRUITS 


31 


Table  2. — Apricots 


Stored  at  8°  F.  to  12°  F 

Date  stored,  July  31,  1919 

Expt. 
No. 

Treatment 
before  storage 

Observations, 
December  5,  1919 

Observations, 
February-March,  1920 

After 
15  days 
at  room 

Color 

Flavor 

Texture 

temperature 

1 

Whole  fruit 

Color  of  skin 
dark,  flavor  good 

Flesh 
light, 
skin 
dark 

Disagree- 
able cold 
storage 
flavor 

Very 

soft 

Spoiled 

2 

Halved  and 
pitted 

Browned  badly, 
flavor  good 

Browned 

Disagree- 
able 
flavor 

Very 
soft 

Spoiled 

2a 

Halved  and 
pitted  in 
water 

Very  bright 
color,  flavor  good 

Bright 

Good, 
fresh 

Rather 
soggy 

3 

Halved  and  pitt- 
ed in  30% 
sugar  syrup 

Color  good;  taste 
somewhat  too 
sweet 

Good 

Excellent 

Better 
than  in 
water 

Sour 

4 

Same  as  No.  3, 
but  50%  syrup 
used 

Color  good, 
sweet,  not 
frozen 

Good 

Very 
good 

Better 
than  in 
water 

Poor 
flavor 

5 

Crushed 

Frozen  solid, 
flavor  good, 
brown  only  on 
top 

Good 

Good, 
fresh 

Spoiled 

6 

Crushed + equal 
sugar 

Not  frozen,  good 
flavor  and  color 

Good 

Very 
good 

No 
change 

7 

Halved,  50% 
sugar  syrup, 
heated  to 
165°  F. 

Good  color, 
tastes  sweeter 
than  No.  4 

Good 

Preserve- 
like flavor 
but  good 

Very 
soft 

Fermented 

8 

Same  as  No.  7, 
but  heated  to 
212°  F. 

Good  color, 
tastes  sweeter 
than  No.  4 

Good 

Not  so 
good  as 
No.  7, 
more  pre- 
served 
flavor 

Very 
soft 

Sour, 
moldy 

13 

Crushed 44 
sugar  and 
boiled 

Stored  at  32  F. : 

Good  color  and 
flavor 

Good 

Not  so 
good  as 
No.  7, 
more  pre- 
served 
flavor 

No 
change 

9 

Same  as  No.  5 

Moldy  by  Aug. 
15,  1919 

10 

Same  as  No.  6 

As  good  as  No.  6 

Good 

Good 

No 

11 

Whole  fruit  (as 
No.  1) 

Moldy  by  Aug. 
20,  1919 

change 

12 

Crushed + equal 
sugar,  heated 
to  212°  F. 

Coating  of  sugar 
on  top,  good 
color  and  flavor 

As 

on  Dec.  5 

As  on  Dec. 
5,  preserve- 
like flavor 

32 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Table  3.' — Loganberries 


Stored  at  8°  F.  to  12°  F. 

Date  stored,  July  3,  1919. 

Expt. 

Treatment 
before  storing 

Notes  on 
August  14,  1919 

Samples  taken  from 
storage  on  January  20,  1920 

Date 
spoiled 

No. 

Color 

Flavor 

Texture 

at  room 
temperature 

1 

None 

Color  and  flavor 
good,  probably 
not  quite  so 
good  as  No.  2 

Natural, 
a  trifle 
bleached 

Aroma 
not  so 
good  as 
No.  3, 
fresh  good 
flavor 

Fair 

January 
23d. 

2 

Crushed 

Frozen,  solid 
mass,  color  and 
flavor  good 

Natural 
or  a 
trifle 
lighter 

Aroma 
not  so 
good  as 
No.  3, 
fresh  good 
flavor 

January 
24th. 

3 

Crushed + equal 
sugar 

Not  frozen, 
flavor  excellent 

Natural 

Rich 

aroma, 

flavor 

very 

sweet, 

excellent 

Some 
berries 
hard; in 
general 
good 

February 
28th  dis- 
continued, 
very 
slight 
deteriora- 
tion 

4 

Crushed + equal 
sugar,  heated 
to  165°  F. 

Not  quite  so 
good  as  No.  2, 
slight  preserved 
flavor 

Natural 

Same  as 
No.  3, 
but  slight 
preserved 
flavor 

Soft 

February 
28th  dis- 
continued, 
very 
slight 
deteriora- 
tion 

5 

Crushed + equal 
sugar,  heated 
to  212°  F. 

Not  quite  so 
good  as  No  2, 
slight  preserve 
flavor 

Natural 

Same  as 
No.  3, 
but  pre- 
served 
flavor 
somewhat 
more  pro- 
nounced 

Soft 

February 
28th  dis- 
continued, 
very 
slight 
deteriora- 
tion 

6 

Crushed,  heated 
to  212°  F. 

Stored  at  32°  F. 

Color  and  flavor 
good,  but  slight 
preserve  flavor 

Natural 

Similar 
to  No.  2 
but  not 
so  fresh 
in  flavor 

Soft 

January 
25th. 

7 

Drawer  of  fruit 

Molded  by 
July  27th. 

Bulletin  324 


STORAGE    OF    PERISHABLE    FRUITS 
Table  4. — Strawberries 


33 


Stored  at  32°  F. 

Date  stored,  July  3,  1919. 

Expt. 

Treatment 
before  storing 

Observations  on 
August  14,  1919 

Samples  removed  from 
storage  January  28,  1920 

Date  of 
spoiling 

No. 

Color 

Flavor 

Texture 

at  room 
temperature 

1 

No  treatment 
(2  baskets) 

Spoiled 

2 

Stemmed 
(2  baskets) 

Spoiled 

16 

Crushed  4-  equal 
sugar 

Flavor  and  color 
good 

Very 

good 

Good 

(very 
sweet) 

Color 
faded  but 
flavor  fair 
on  March 
6,  1920 
when  dis- 
carded 

21 

Crushed + equal 
sugar  and 
heated  to 
212°  F. 

Slight  preserve 
flavor,  color 
good 

Good, 

very 

slightly 

faded  and 

somewhat 

brownish 

Slight 

preserve 

flavor; 

too 

sweet 

Color 
faded  but 
flavor  fair 
on  March 
6,  1920 
when  dis- 
carded 

22 

Crushed  +1§ 
wt.  sugar, 
heated  to 
212°  F. 

Stored  at  8°  F.  to 
12°  F.: 

Slight  preserve 
flavor,  color 
good 

Good, 
but  very 
slightly 
faded 

Preserve 
flavor 

Color 

faded  but 
flavor  fair 
on  March 
6,  1920 
when  dis- 
carded 

8 

Stemmed 

(4  baskets) 

Frozen  solid, 
color  and  flavor 
good 

Good, 

slightly 
bleached 

Fresh 

Soft 

3 

Stemmed,  stored 
in  water 

Flavor  very  good, 
some  color  in 
the  water 

Natural, 
good 

Fresh, 

very 

good 

Soft 

January 
31st. 

4 

Stemmed,  stored 
in  10%  sugar 
syrup 

Better  than 
No.  3  for  flavor, 
some  color  in 
syrup 

Natural, 
good 

Fresh, 
excellent 

Soft 

February 
2d.  (sour) 

5 

Stemmed,  stored 
in  20%  sugar 
syrup 

Better  than 
No.  3  for  flavor, 
some  color  in 
syrup 

Natural, 
good 

Good 

excellent 

Soft 

February 
2d.  (sour) 

6 

Stemmed,  stored 
in  40%  sugar 
syrup 

Better  than 
No.  3  for  flavor 

Natural, 
good 

Good 

(sweet) 

Soft 

February 
4th. 

34 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Table  4.- — Strawberries — {Continued) 


Stored  at  8°  F.  to  12°  F 

Date  stored,  July  3,  1919. 

Samples  removed  from 

storage  January  28,  1920 

Date 

Expt. 

Treatment 

Observations  on 

of  spoiling 

No. 

before  storing 

August  14,  1919 

at  room 

Color 

Flavor 

Texture 

temperature 

7 

Stemmed,  stored 

Better  than 

Natural, 

Good, 

Soft 

February 

in  60%  sugar 

No.  3  for  flavor, 

good 

but  some 

6th. 

syrup 

some  color  in 
syrup 

what  too 
sweet 

9 

Crushed  berries, 

Flavor  and  color 

Natural, 

Good, 

February 

no  sugar 

good 

good 

fresh 

2d.  (sour) 

10 

Crushed  berries 

Flavor  and  color 

Natural, 

Very 

February 

+-J  wt.  of 

better  than 

good 

good 

6th. 

sugar 

No.  9 

(sweet 
taste) 

11 

Crushed  berries 

Flavor  and  color 

Natural, 

Very 

February 

+|  wt.  of 

better  than 

good 

good 

16th. 

sugar 

No.  9,  plastic 

(sweet 
taste) 

12 

Crushed  berries 

Nearly  unfrozen, 

Natural, 

Very 

Color  im- 

+ M  wt.  of 

color  good 

good 

good 

paired  but 

sugar 

(quite 

sweet) 

flavor  fair  ; 
discon- 
tinued on 
March  6th 

13 

Crushed  berries 

Unfrozen, 

Natural, 

Very 

Color  im- 

+equal  wt.  of 

color  good 

good 

good 

paired  but 

sugar 

(very 
sweet) 

flavor  fair; 
discon- 
tinued on 
March  6th 

14 

Crushed  berries 

Unfrozen,  too 

Natural, 

Very 

Color  im- 

+ Hwt.  of 

syrupy,  color 

good 

good 

paired  but 

sugar 

good,  berries 
tend  to  float 

(too 
sweet) 

flavor  fair; 
discon- 
tinued on 
March  6th 

15 

Crushed  berries 

Unfrozen,  too 

Natural, 

Very 

Color  im- 

+ U  wt.  of 

syrupy,  color 

good 

good 

paired  but 

sugar 

good,  berries 
tend  to  float 

(too 
sweet) 

flavor  fair; 
discon- 
tinued on 
March  6th 

17 

Same  as  No.  11, 

Flavor  scarcely 

Slight 

Sweet, 

February 

but  heated  to 

as  fresh  as  No. 

darken- 

slight 

20th. 

165°  F. 

11,  some  pre- 
serve flavor 

ing 

preserve 
flavor 

( 
Very 

18 

Same  as  No.  13, 

Syrupy,  color 

Good, 

March  6th 

but  heated  to 

good 

but 

sweet, 

color  im- 

165° F. 

slight 
darkening 

some 

preserve 

flavor 

paired, 
flavor  fair ; 
discon- 
tinued 

Bulletin  324 


STORAGE    OF    PERISHABLE    FRUITS 


35 


Table  4. — Strawberries — {Continued) 


Stored  at  8°  F.  to  12°  F. 


Date  stored,  July  3,  1919. 


Expt. 

Treatment 
before  storing 

Observations  on 
August  14,  1919 

Samples  removed  from 
storage  January  28,  1920 

Date 
spoiling 

No. 

Color 

Flavor 

Texture 

at  room 
temperature 

19 

Same  as  No.  15, 
but  heated  to 
165°  F. 

Syrupy,  color 
good 

Good, 
but 
slight 
darkening 

Too 

sweet, 

some 

preserve 

flavor 

March  6th 
color  im- 
paired, 
flavor  fair; 
discon- 
tinued 

20 

Same  as  No.  13, 
but  heated  to 
212°  F. 

Preserve  flavor, 
color  deeper  red 
than  No.  13 

Darken- 
ing of 
natural 
color 

Very 

sweet, 

more 

preserve 

flavor 

than 

No.  18 

23 

Whole  berries, 
stemmed + 
equal  sugar 
and  heat  to 
212°  F.  for 
4  minutes 

Preserve  flavor 
marked,  color 
decidedly 
darker 

Dark  red 

not 

natural 

red 

Very 

sweet, 

more 

preserve 

flavor 

than 

No.  18 

Fair,  as 

in 

preserves 

Color 
nearly 
unchang- 
ed, flavor 
same 

24 

Same  as  No.  23, 
but  l\  sugar 
by  weight 
added  at  room 
temperature 

Preserve  flavor 
marked,  color 
decidedly 
darker 

Dark  red 
not 

natural 
red 

Too 
sweet 

Fair,  as 
in  pre- 
serves 

Color 
nearly 
unchang- 
ed, flavor 
same 

25 

Strawberries  + 
equal  weight 
of  sugar  heat- 
ed to  boiling 
and  sealed  hot 
in  jars,  stored 
at  room  tem- 
perature 

Quality  and 
color  fair 

Bleached 
to  light 
brown 

Poor 

Soft 

36 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Table  5. — Red  Raspberries  and  Currants 


Stored  July  3,  1919 

Observations,  January  20,  1920,  on 

Date 

Expt. 

Treatment 

Observations, 

thawed  samples  from  storage 

of  spoiling 

No. 

before  storing 

August  14,  1919 

at  room 

temperature 

Color 

Flavor 

Texture 

Raspberry* 

1 

No  treatment 

Solid,  color  good 

Very 

Very 

Fair  to 

January 

flavor  good 

good 

good 

soft 

23d. 

Raspberry* 

2 

Crushed +f 

Plastic,  color 

Very- 

Very 

Seeds 

February 

wt.  of  sugar 

and  flavor  good 

good 

sweet, 
excellent 

con- 
spicuous 

12th. 

Raspberry* 

3 

Same  as  No  2 

Plastic,  color 

Good 

Very 

Seeds 

February 

but  heated  to 

good,  flavor  not 

sweet, 

con- 

16th. 

165°  F. 

quite  as  good  as 
No.  2 

excellent 

spicuous 

Raspberry* 

4 

Same  as  No.  2 

Plastic,  color 

Good 

Very 

Seeds 

February 

but  heated  to 

good,  flavor  not 

sweet, 

con- 

16th. 

212°  F. 

quite  as  good  as 

No.  2 

excellent 

spicuous 

Raspberry* 

5 

Crushed,  heated 

Solid,  color  and 

Good 

Very 

Seeds 

January 

to  212°  F. 

flavor  good 

sweet, 
excellent 

con- 
spicuous 

23d. 

Raspberry! 

6 

Untreated 

Date  of  mould- 
ing earlier  than 
August  14th. 

, 

7 

Raspberry! 

Made  into  jam 

Color  and  flavor 

Brown 

Poor 

Poor 

and  stored  at 

good 

room  temper- 

ature 

Currants  (red)  * 

1 

No  treatment 

Solid,  color  and 
flavor  good 

Good 

Good 

Soft 

January 
23d. 

2 

Currants  (red)* 

Crushed+equal 

Unfrozen,  fresh 

Good 

Excellent 

Test  dis- 

sugar 

color  and  taste 

very 
sweet 

continued 
on  Feb- 
ruary 28th 
flavor 
slightly 
stale 

Currants  (red)* 

3 

Crush + equal 

Darker  than 

Good 

Not  as 

Test  dis- 

sugar, heat  to 

No.  2,  unfrozen 

fresh  as 

continued 

212°  F. 

No.  2, 
more 
preserved 
taste 

on  Feb- 
ruary 28th 
flavor 
slightly 
stale 

''Stored  at  8°  F.-120  F.        tutored  at  82°  F. 


Bulletin  324 


STORAGE  OF  PERISHABLE  FRUITS 


37 


Table  6.— Grape  Juice  at  8°  F.  to  12°  F. 

On  September  20th,  1919,  several  lots  of  ripe  grapes  of  the  varieties  indicated  in  the 
following  table  were  received  from  the  University  Farm.  The  red  varieties  were  crushed; 
heated  to  150°  F.,  and  pressed  to  extract  the  color.  White  varieties  were  crushed  and 
pressed  only.  The  juices  were  strained  and  placed  in  cold  storage  at  8°  F.  to  12°  F.  in  open 
stoneware  crocks.  Check  lots  of  the  same  juice  were  pasteurized  at  165°  F.  in  glass  bottles 
and  stored  at  room  temperature  for  future  comparison  with  the  lots  from  cold  storage. 


Lot 

Variety 

Treatment 

Observations,  May  11,  1920 

1 

Alicante 
Bouschet 

Stored  at  8°  F.  to  12°  F. 

Color  deep  purplish  red,  flavor  good, 
rich  and  fresh.  No  cooked  taste. 
Superior  to  No.  2 

2 

Alicante 
Bouschet 

Pasteurized  at  165°  F., 
stored  at  room  temper- 
ature 

Inferior  to  No.  1  in  color,  flavor,  and 
aroma;   noticeable   cooked  taste;   color 
brownish  red 

3 

Muscat 

Stored  at  8°  F.  to  12°  F. 

Flavor  and  aroma  equal  to  those  of  fresh 
grapes  although  not  so  intense.  Pro- 
bably some  flavor  and  aroma  have 
evaporated.     Much  superior  to  No.  4 

4 

Muscat 

Pasteurized  at  165°  F., 
stored  at  room  temper- 
ature 

Inferior  to  No.  3;  "raisin  pie"  flavor 

5 

Muscat + 
Alicante 
Bouschet 

Stored  at  8°  F.  to  12°  F. 

Rich  Muscat  flavor;  color  purplish  red; 
much  superior  to  No.  6 

6 

Muscat  + 
Alicante 
Bouschet 

Pasteurized.     Stored  at 
room  temperature 

Inferior  to  No.  5.  Color  brownish  red. 
Flavor  cooked.  Aroma  poor.  Juice  is 
better  than  average  commercial  juice 

7 

Isabella 

Stored  at  8°  F.  to  12°  F. 

Very  rich  Isabella  flavor  and  aroma. 
Color  deep  purplish  red 

8 

Isabella 

Pasteurized,    stored   at 
room  temperature 

Inferior  to  No.  7.  Color  brownish  red. 
Flavor  noticeably  cooked 

9 

Petite  Sirah 

Stored  at  8°  F.  to  12°  F. 

Flavor  about  same  as  fresh  juice.  Color 
deep  purplish  red.  No  noticeable  cook- 
ed taste 

10 

Petite  Sirah 

Pasteurized,    stored   at 
room  temperature 

Inferior  to  juice  No.  9.  Color  brownish 
red.     Flavor  cooked 

38  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

DISCUSSION    OF   TABLES 

From  the  results  given  in  the  foregoing  tables  certain  conclusions 
may  be  drawn.  The  discussion  of  the  results  of  the  various  tables 
will  be  taken  up  according  to  the  individual  fruits. 

Cherries. — Untreated  cherries  in  open  containers  stored  at  8°-12°  F. 
soon  became  brown  in  color  throughout  by  oxidation.  This  held  true 
for  both  the  pitted  and  unpitted  fruit. 

Freezing  the  untreated  cherries  in  water  prevented  darkening 
of  the  color  during  storage  probably  as  a  result  of  the  exclusion  of  air. 

The  natural  light  pink  color  of  the  Royal  Anne  was  well  preserved 
by  this  method.  The  substitution  of  syrups  varying  from  10-40% 
cane  sugar  content  seemed  to  be  no  improvement  over  water  as  a 
storage  medium,  in  so  far  as  retention  of  color,  quality  and  texture 
of  the  fresh  fruit  was  concerned,  although  these  syrups  added  some- 
thing to  the  flavor. 

Heating  the  fruit  to  175°  F.  in  water  or  dilute  syrups  before 
storage  resulted  in  bleaching  of  the  color  of  the  cherries  and  in  the 
imparting  of  a  noticeable  cooked  taste.  Heating  to  212°  F.  intensified 
these  defects  giving  a  product  very  similar  to  ordinary  canned  cherries. 
Therefore,  heating  the  fruit  before  storage  seems  inadvisable  and  an 
unnecessary  expense. 

Untreated  cherries  stored  at  32°  F.  soon  became  moldy.  No  storage 
tests  of  this  fruit  in  syrups  at  32°  F.  were  made. 

Cherries  stored  in  sulfurous  acid  by  the  usual  commercial  methods 
were  inferior  in  flavor  to  those  stored  by  the  various  freezing  methods 
noted  above. 

Apricots. — This  fruit  gave  excellent  results  in  several  methods  of 
storage  at  8°-12°  F.  because  of  its  stable  color  and  rich  flavor. 

The  skin  of  whole  untreated  fruit  stored  at  8°-12°  F.  became 
brown;  both  the  skin  and  flesh  of  the  halved  untreated  fruit  became 
brown  at  8°-12°  F.  The  fruit  in  both  cases  after  several  months' 
storage  developed  a  very  disagreeable  ' '  cold  storage ' '  flavor  rendering 
the  products  made  from  them  almost  inedible. 

The  halved  fruit  stored  at  8°-12°  F.  in  water  or  in  syrups  of  30% 
and  50%  cane  sugar,  retained  a  remarkably  fresh  flavor  and  color, 
although  the  fruit  softened  noticeably  on  thawing.  It  appeared  equal 
in  all  other  respects  to  the  fresh  fruit. 

The  crushed  fruit  with  an  equal  weight  of  sugar  added  and  stored 
at  8°-12°  F.  retained  its  fresh  flavor  and  color  in  an  excellent  manner. 
It  was  found  very  suitable  for  ice  cream,  short  cake,  etc.  Very  ripe 
fruit  required  only  about  one-half  its  weight  of  sugar  to  give  good 


Bulletin  324  STORAGE    OF    PERISHABLE    FRUITS  39 

results.  Fruit  crushed  and  with  no  sugar  added,  became  brown  at 
the  surface,  but  the  remainder  of  the  lot  to  which  air  had  no  access 
was  of  excellent  fresh  color  and  flavor,  indicating'  that  sugar  is  not 
necessary  for  the  retention  of  flavor  and  color  of  the  crushed  fruit. 

Crushed  fruit  at  32°  F.  spoiled  in  about  two  weeks.  Crushed  fruit 
plus  an  equal  weight  of  sugar  stored  at  32°  kept  perfectly.  This 
same  mixture  heated  to  212°  F.  and  stored  at  32°  F.  kept  well,  but 
possessed  an  tl apricot  preserve"  flavor.  The  unheated  fruit  was 
preferable  to  the  cooked  article  and  much  superior  in  flavor  to  the 
ordinary  canned  apricot  of  commerce. 

Logwmberries. — Fewer  tests  were  made  upon  this  fruit  than  upon 
strawberries.  Because  of  its  extremely  rich  and  permanent  flavor  as 
well  as  its  deep  color,  the  loganberry  is  a  very  satisfactory  fruit  for 
freezing  storage. 

The  fruit  kept  fairly  well  without  treatment  at  8°-12°  F.  There 
was,  however,  considerable  shriveling  and  some  loss  of  color  and  flavor. 

Untreated  crushed  fruit  kept  perfectly  and  seemed  equal  to  the 
fresh  fruit  in  every  way.  Sugar  added  to  the  crushed  fruit  reduced 
its  tart  flavor  and  made  the  fruit  richer  than  the  unsweetened  article. 

Heating  the  crushed  and  sweetened  fruit  to  165°  F.  and  212°  F. 
imparted  a  noticeable  "jam "-like  flavor.  Heating  is  not  recom- 
mended although  it  does  deepen  the  color  of  the  juice  and  softens 
the  fruit.  Unheated  sweetened  fruit  if  not  thoroughly  crushed  tended 
to  become  hard  through  the  effect  of  the  sugar's  removing  moisture 
from  the  berries.     . 

Untreated  fruit  at  32°  F.  became  moldy  in  less  than  three  weeks 
time.    No  tests  of  sweetened  fruit  were  made  at  this  temperature. 

Bed  Raspberries. — This  fruit  required  less  sugar  than  loganberries 
for  the  imparting  of  a  rich  flavor. 

The  untreated  fruit  at  8°  F.  to  12°  F.  shriveled  slightly  but 
retained  its  color  and  flavor  well. 

The  crushed  fruit  plus  two-thirds  its  weight  of  sugar  retained  more 
of  the  fresh  fruit  aroma  and  flavor  than  did  the  unsweetened  fruit. 
This  amount  of  sugar  rendered  the  fruit  very  sweet  in  flavor;  a 
slightly  smaller  proportion  would  have  been  sufficient.  The  seeds  of 
the  crushed  berries  were  quite  conspicuous. 

Heating  the  fruit  to  212°  F.  before  storage  imparted  a  cooked 
flavor.     The  unheated  fruit  was  preferable  to  the  heated  product. 

Currants. — Untreated  currants  at  8°-12°  F.  retained  their  color 
and  flavor  remarkably  well  and  were  as  suitable  for  jelly  and  jam 
as  the  fresh  fruit.  The  crushed  fruit  to  which  was  added  an  equal 
weight  of  sugar  retained  its  fresh  flavor  to  a  greater  degree  than  did 


40  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

the  untreated  fruit.  Heating-  the  crushed  fruit  to  boiling  before 
storage  injured  the  quality  slightly  and  is  not  recommended. 

Strawberries. — Strawberries  held  untreated  at  32°  F.  spoiled  in 
less  than  six  weeks.  The  same  fruit  after  crushing  and  mixing  with 
an  equal  weight  of  sugar  retained  very  well  its  flavor,  color  and  aroma 
without  molding  or  fermenting  at  32°  F.  Heating  the  crushed  fruit 
and  sugar  before  storage  injured  the  color  and  flavor.  The  use  of 
one  and  one-half  times  as  much  sugar  as  fruit  was  tested,  but  this 
amount  of  sugar  is  not  necessary  and  rendered  the  fruit  too  sweet. 

Berries  frozen  in  water  or  dilute  syrups  and  stored  at  8°-12°F. 
were  superior  to  the  same  fruits  stored  untreated  at  this  same  tem- 
perature. The  berries  tended  to  float  in  very  heavy  syrups.  The 
flavor  and  color  of  the  fruit  stored  in  water  was  as  good  as  those  of 
the  lots  stored  in  syrups.  Untreated  berries  in  open  containers 
shriveled  slightly  and  lost  some  of  their  color. 

Crushed  unsweetened  berries  retained  their  flavor  and  color  very 
well  at  8°-12°  F.  The  addition  of  sugar  to  the  crushed  berries  before 
storage  made  the  flavor  richer  but  this  addition  is  not  necessary. 
With  more  than  an  equal  weight  of  sugar  the  crushed  fruit  tended 
to  float. 

Heating  the  crushed  fruit  impaired  the  color  and  quality. 

Strawberries  preserved  by  the  usual  household  method  by  cooking 
with  an  equal  weight  of  sugar  and  storing  in  sealed  containers  were 
much  inferior  to  fruit  preserved  at  8°-12°  F.  after  similar  prelim- 
inary treatment;  and  very  much  inferior  to  the  sweetened  unheated 
fruit  stored  at  8°-12°  F. 

Grape  Juice. — All  grape  juices  stored  8°-12°  F.  were  very  much 
superior  in  every  respect  to  the  same  juices  preserved  by  pasteurizing 
at  165°  F.  The  bright  fresh  color  of  the  juices  from  cold  storage  was 
in  great  contrast  to  the  brownish  red  color  of  the  pasteurized  juices. 

Pasteurized  Muscat  juice  possesses  a  strong  characteristic  "raisin" 
flavor;  the  juice  held  at  8°-12°  F.  resembles  the  fresh  juice  in  flavor 
and  aroma. 

The  juices  in  cold  storage  were  held  in  open  containers,  a  con- 
dition which  resulted  in  considerable  volatilization  of  flavor  and 
aroma.  Doubtless  sealed  containers  would  greatly  reduce  this  loss.  In 
general,  the  quality  of  the  cold  stored  juices  was  so  much  superior 
to  that  of  the  pasteurized  juices  that  freezing  as  a  means  of  preserving 
fruit  juices  should  in  time  compete  with  pasteurization. 

Preliminary  tests  with  apple  juice  indicate  that  it  also  retains  its 
flavor  and  aroma  very  well  at  8°-12°  F. 


BULLETIN  324  STORAGE    OF    PERISHABLE    FRUITS  41 

UTILIZATION    OF    FRUITS    FROM    FREEZING    STORAGE 

The  fruit  from  the  more  important  experiments  described  else- 
where in  this  report  were  made  into  various  products  such  as  jellies, 
jams,  canned  fruits,  preserves,  candied  fruits  and  ice  cream. 

Cherries  held  in  freezing  storage  in  water  or  syrup  gave  excellent 
results  for  candying,  for  preserves,  for  cooking  purposes  and  for  can- 
ning. Those  stored  untreated  in  open  containers  were  brown  in 
color  and  inferior  in  flavor  for  the  above  purposes,  to  fruit  stored 
in  water  or  syrup.  The  texture  of  the  products  was  in  all  cases  good. 
Storage  of  pitted  cherries  in  water  at  8°-12°  F.  should  prove  a  satis- 
factory method  of  storing  the  fruit  for  use  in  the  preparation  of 
Maraschino  and  candied  cherries.  This  product  is  certainly  more 
wholesome  and  more  attractive  in  flavor  than  is  the  same  fruit  held 
in  sulfurous  acid  solution.  Cherries  stored  without  treatment  were 
not  so  satisfactory  for  pies  as  were  those  stored  under  water. 

Apricots  stored  untreated  in  open  containers  became  brown  in 
color  and  developed  a  very  disagreeable  flavor  which  precluded  their 
satisfactory  use  in  preserves,  etc.  The  fruit  held  at  8°-12°  F.  under 
water  or  syrup  was  excellent  for  jams  and  marmalades,  although  some- 
what soft  for  canning.  The  flavor  of  jams  made  from  this  fruit  was 
equal  to  that  of  the  same  products  made  from  the  fresh  fruit. 

Crushed  apricots  preserved  at  8°-12°  F.  with  an  equal  weight 
of  sugar  produced  an  ice  cream  of  very  rich  fresh  fruit  flavor  and 
of  excellent  color.  No  additional  sugar  was  necessary  in  preparing 
the  ice  cream.  The  crushed  unsweetened  apricots  made  an  excellent 
ice  cream  after  sweetening  with  sufficient  sugar.  The  heated  fruit 
produced  an  ice  cream  of  very  pleasing  flavor,  but  slightly  darker 
in  color  with  more  of  a  cooked  flavor  than  did  the  other  two  lots.  As 
a  check  ice  cream  was  made  from  home  preserved  apricots.  Although 
of  good  quality,  this  ice  cream  was  not  equal  in  flavor  to  that  prepared 
from  the  unheated  crushed  fruit. 

The  tests  clearly  demonstrated  the  superiority  of  the  crushed 
unheated  fruit  from  cold  storage  for  use  in  ice  cream  and  other  frozen 
dishes  where  the  fresh  rather  than  the  "preserved"  flavor  of  the  fruit 
is  desired. 

Strawberries  yielded  results  in  the  preparation  of  various  products 
similar  to  those  obtained  with  apricots.  The  unsweetened  crushed 
fruit,  the  crushed  unheated  sweetened  fruit  and  the  crushed  sweetened 
fruit  heated  to  165°  F.  before  storage  were  used  in  ice  cream  making. 
Of  these  the  unheated,  unsweetened  crushed  fruit  gave  the  best  flavor. 
The  fruit  heated  to  165°  F.  gave  a  slightly  darker  ice  cream  of  less 


42  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

fresh  fruit  flavor  than  did  the  other  two  lots,  but  was  still  of  very 
pleasing  quality. 

The  crushed  sweetened  berries  were  used  successfully  without 
further  sweetening  in  short  cakes.  The  flavor  and  color  of  this  fruit 
for  this  purpose  were  equal  to  those  of  the  fresh  fruit. 

Using  the  fruit  from  cold  storage,  a  comparison  was  made  of  the 
quality  of  strawberry  jams  and  preserves  made  by  the  usual  open 
kettle  process  and  by  cooking  under  a  vacuum.  The  latter  process 
gave  products  of  remarkably  fresh  fruit  flavor  and  color;  superior  in 
every  way  to  the  usual  kettle-cooked  article.  The  same  results  were 
obtained  with  loganberries,  red  raspberries  and  apricots.  This  method 
deserves  attention  from  preserve  manufacturers. 

Loganberries  from  the  cold  storage  tests  previously  described  were 
tested  for  ice  cream  and  for  pies.  The  results  were  similar  to  those 
obtained  with  strawberries.  The  crushed  fruit  was  very  satisfactory 
when  used  on  ice  cream  "sundaes"  and  should  be  excellent  for  ice 
cream  sodas  and  similar  fountain  specials. 

The  unsweetened  fruit  was  satisfactory  for  jelly  making,  giving 
a  jelly  of  good  color,  flavor  and  texture,  but  for  some  reason  not 
yet  clearly  understood,  the  sweetened  fruit  failed  to  give  a  firm  jelly. 
This  same  trouble  was  also  encountered  with  sweetened  currants  from 
freezing  storage. 

Raspberries  crushed,  sweetened  with  two-thirds  of  their  weight 
of  sugar  and  held  at  8°-12°  F.  gave  excellent  ice  cream.  This  crushed 
fruit  was  also  very  satisfactory  for  use  as  a  jam  or  spread  for  bread 
or  as  a  dressing  for  ice  cream  sundaes,  etc.  The  heated  fruit  was 
satisfactory,  but  not  of  quite  such  fresh  flavor  as  the  unheated. 

Currants  stored  without  sugar  gave  good  results  in  jelly  making. 
The  product  was  equal  in  every  way  to  that  made  from  the  fresh 
fruit.  i     :    i;     I:  ,     IHJ     I 

In  general,  fruits  of  the  varieties  used  in  the  tests  were  after  six 
to  ten  months  at  8°-12°  F.  equal  to  the  fresh  fruits  for  most  purposes. 

SUMMARY 

1.  Soft  fruits  such  as  apricots,  cherries  and  berries  can  be  pre- 
served at  cold  storage  temperatures  of  32°  F.  for  not  more  than  a 
week  to  three  weeks.  Present  commercial  methods  of  storing  these 
fruits  at  temperatures  lower  than  32°  F.  are  not  standardized  and 
are  in  many  cases  unsatisfactory. 

2.  These  fruits  if  held  in  water  or  syrup  at  8°-12°  F.  retain  their 
flavor  and  color  very  well  for  at  least  a  year.    Lots  of  certain  of  these 


BULLETIN  324  STORAGE    OF    PERISHABLE    FRUITS  43 

same  fruits  held  at  8°-12°  F.  in  open  containers  without  liquid,  in 
time  lose  color  and  flavor.  This  is  especially  true  of  cherries,  which 
become  brown,  and  of  apricots  which  in  time  develop  a  disagreeable 
"cold  storage"  flavor  and  a  brown  color.  Berries  in  open  baskets 
retain  their  color  and  flavor  very  well. 

3.  The  crushed  fruits  with  or  without  sugar  retained  their  color 
and  flavor  almost  perfectly  at  8°-12°  F.  for  almost  a  year;  the  dura- 
tion of  these  tests.  This  fruit  was  excellent  for  ice  cream,  for  pies, 
for  use  as  a  jam  on  bread,  for  shortcakes  and  general  soda  fountain 
use. 

4.  Grape  juice  stored  at  8°-12°  F.  was  very  much  superior  to  the 
juice  preserved  by  pasteurization. 

5.  Former  brewing  plants  are  well  equipped  for  undertaking  the 
storage  of  soft  fruits  and  fruit  juices  by  the  methods  discussed  and 
recommended  in  this  report.  The  storage  of  these  fruits  should  form 
a  profitable  method  of  utilizing  such  otherwise  idle  equipment. 

6.  The  storage  of  these  fruits  will  be  studied  further  during  the 
present  fruit  season. 


STATION  PUBLICATIONS   AVAILABLE   FOR   FREE   DISTRIBUTION 


BULLETINS 


No. 

168.  Observations  on  Some  Vine  Diseases  in 

Sonoma  County. 

169.  Tolerance  of  the  Sugar  Beet  for  Alkali. 
185.  Report  of  Progress  in  Cereal  Investiga- 
tions. 

208.  The  Late  Blight  of  Celery. 

250.  The  Loquat. 

251.  Utilization  of  the  Nitrogen  and  Organic 

Matter    in    Septic    and    Imhoff    Tank 
Sludges. 

252.  Deterioration  of  Lumber. 

253.  Irrigation    and    Soil    Conditions    in    the 

Sierra  Nevada  Foothills,  California. 
257.  New  Dosage  Tables. 

261.  Melaxuma  of  the  Walnut,  "  Juglans  regia." 

262.  Citrus    Diseases    of    Florida    and    Cuba 

Compared  with  Those  of  California. 

263.  Size  Grades  for  Ripe  Olives. 

266.  A  Spotting  of  Citrus  Fruits  Due  to  the 

Action  of  Oil  Liberated  from  the  Rind. 

267.  Experiments  with  Stocks  for  Citrus. 

268.  Growing  and  Grafting  Olive  Seedlings. 

270.  A  Comparison  of  Annual  Cropping,  Bi- 

ennial  Cropping,   and   Green   Manures 
on  the  Yield  of  Wheat. 

271.  Feeding  Dairy  Calves  in  California. 

272.  Commercial  Fertilizers. 

273.  Preliminary    Report    on    Kearney    Vine- 

yard Experimental  Drain. 

274.  The  Common  Honey  Bee  as  an  Agent  in 

Prune  Polination. 

275.  The  Cultivation  of  Belladonna  in   Cali- 

fornia. 

276.  The  Pomegranate. 

277.  Sudan  Grass. 

278.  Grain  Sorghums. 

279.  Irrigation  of  Rice  in  California. 

280.  Irrigation   of  Alfalfa  in  the   Sacramento 

Valley. 

282.  Trials  with   California   Silage   Crops   for 

Dairy  Cows. 

283.  The  Olive  Insects  of  California. 


No. 

285. 
286. 
288. 

290. 

297. 
298. 
299. 
300. 
301. 

302. 

303. 
304. 

308.  I. 


309.  I. 

310. 
311. 
312. 
313. 
314. 
316. 
317. 
318. 
319. 
320. 
321. 
322. 
323. 

324. 

325. 


The  Milch  Goat  in  California. 

Commercial  Fertilizers. 

Potash  from  Tule  and  the  Fertilizer 
Value  of  Certain  Marsh  Plants. 

The  June  Drop  of  Washington  Navel 
Oranges. 

The  Almond  in  California. 

Seedless  Raisin  Grapes. 

The  Use  of  Lumber  on  California  Farms. 

Commercial  Fertilizers. 

California  State  Dairy  Cow  Competition, 
1916-18. 

Control  of  Ground  Squirrels  by  the 
Fumigation  Method. 

Grape  Syrup. 

A  Study  on  the  Effects  of  Freezes  on 
Citrus  in  California. 
Fumigation  with  Liquid  Hydrocianic 
Acid.  II.  Physical  and  Chemical  Pro- 
perties of  Liquid  Hydrocianic  Acid. 
The  Carob  in  California.  II.  Nutri- 
tive Value  of  the  Carob  Bean. 

Plum  Pollination. 

Investigations  with  Milking  Machines. 

Mariout  Barley. 

Pruning  Yound  Deciduous  Fruit  Trees. 

Cow-Testing  Associations  in  California. 

The  Kaki  or  Oriental  Persimmon. 

Selections  of  Stocks  in  Citrus  Propagation. 

The  Effects  of  Alkali  on  Citrus  Trees. 

Caprifigs  and  Caprification. 

Control  of  the  Coyote  in  California. 

Commercial  Production  of  Grape  Syrup. 

The  Evaporation  of  Grapes. 

Heavy  vs.  Light  Grain  Feeding  for  Dairy 
Cows. 

Storage  of  Perishable  Fruit  at  Freezing 
Temperatures. 

Rice  Irrigation  Measurements  and  Ex- 
periments in  Sacramento  Valley,  1914- 
1919. 


No. 
65. 
70. 

76. 
82. 

87. 
109. 


111. 

113. 
114. 
115. 
117. 

124. 
126. 
127. 
128. 
129. 
130. 
131. 
133. 
135. 
136. 
137. 
138. 
139. 


CIRCULARS 
No. 

The  California  Insecticide  Law.  140. 
Observations    on    the    Status     of    Corn 

Growing  in  California. 

Hot  Room  Callusing.  143. 
The      Common      Ground      Squirrels      of 

California.  144. 

Alfalfa.  147. 

Community  or  Local  Extension  Work  by  148. 

the  High  School  Agricultural  Depart-  152. 

ment. 

The  use  of  Lime  and  Gypsum  on  California  153. 

Soils. 

Correspondence  Courses  in  Agriculture.  154. 
Increasing  the  Duty  of  Water. 

Grafting  Vinifera  Vineyards.  155. 

The  Selection  and  Cost  of  a  Small  Pump-  156. 

ing  Plant.  157. 

Alfalfa  Silage  for  Fattening  Steers.  158. 

Spraying  for  the  Grape  Leaf  Hopper.  159. 

House  Fumigation.  160. 

Insecticide  Formulas.  164. 

The  Control  of  Citrus  Insects.  165. 
Cabbage  Growing  in  California. 

Spraying  for  Control  of  Walnut  Aphis.  167. 

County  Farm  Adviser.  168. 
Official  Tests  of  Dairy  Cows. 

Melilotus  Indica.  169. 

Wood  Decay  in  Orchard  Trees.  170. 
The  Silo  in  California  Agriculture. 

The  Generation  of  Hydrocyanic  Acid  Gas  172. 

in  Fumigation  by  Portable  Machines.  173. 


The   Practical   Application   of   Improved 

Methods  of  Fermentation  in  California 

Wineries  during  1913  and  1914. 
Control     of     Grasshoppers    in     Imperial 

Valley. 
Oidium  or  Powdery  Mildew  of  the  Vine. 
Tomato  Growing  in  California. 
"Lungworms". 
Some  Observations  on  the  Bulk  Handling 

of  Grain  in  California. 
Announcement    of    the    California    State 

Dairy  Cow  Competition,  1916-18. 
Irrigation    Practice    in    Growing    Small 

Fruits  in  California. 
Bovine  Tuberculosis. 
How  to  Operate  an  Incubator. 
Control  of  the  Pear  Scab. 
Home  and  Farm  Canning. 
Agriculture  in  the  Imperial  Valley. 
Lettuce  Growing  in  California. 
Small  Fruit  Culture  in  California. 
Fundamentals    of    Sugar    Beet    Culture 

under  California  Conditions. 
Feeding  Stuffs  of  Minor  Importance. 
Spraying  for  the  Control  of  Wild  Morning- 

Glory  within  the  Fog  Belt. 
The  1918  Grain  Crop. 
Fertilizing  California  Soils  for  the   1918 

Crop. 
Wheat  Culture. 
The  Construction  of  the  Wood-Hoop  Silo. 


CIRCULARS— Continued 


No. 

174.  Farm  Drainage  Methods. 

175.  Progress  Report  on  the   Marketing  and 

Distribution  of  Milk. 

176.  Hog  Cholera  Prevention  and  the  Serum 

Treatment. 

177.  Grain  Sorghums. 

178.  The  Packing  of  Apples  in  California. 

179.  Factors  of  Importance  in  Producing  Milk 

of  Low  Bacterial  Count. 

181.  Control  of  the  California  Ground  Squirrel. 

182.  Extending  the  Area  of  Irrigated  Wheat  in 

California  for  1918. 

183.  Infectious  Abortion  in  Cows. 

184.  A  Flock  of  Sheep  on  the  Farm. 

185.  Beekeeping  for  the  Fruit-grower  and  Small 

Rancher  or  Amateur. 

187.  Utilizing  the  Sorghums. 

188.  Lambing  Sheds. 

189.  Winter  Forage  Crops. 

190.  Agriculture  Clubs  in  California. 

191.  Pruning  the  Seedless  Grapes. 

193.  A  Study  of  Farm  Labor  in  California. 

195.  Revised  Compatibility  Chart  of  Insecti- 
cides and  Fungicides. 

197.  Suggestions  for  Increasing  Egg  Produc- 
tion in  a  Time  of  High-Feed  Prices. 


No. 

198.  Syrup  from  Sweet  Sorghum. 

201.  Helpful  Hints  to  Hog  Raisers. 

202.  County     Organization     for     Rural     Fire 

Control. 

203.  Peat  as  a  Manure  Substitute. 

204.  Handbook    of   Plant    Diseases   and    Pest 

Control. 

205.  Blackleg. 

206.  Jack  Cheese. 

207.  Neufchatel  Cheese. 

208.  Summary  of  the  Annual  Reports  of  the 

Farm  Advisors  of  California. 
210.  Suggestions  to  the  Settler  in  California. 

213.  Evaporators  for  Prune  Drying. 

214.  Seed   Treatment   for    the    Prevention    of 

Cereal  Smuts. 

215.  Feeding  Dairy  Cows  in  California. 

216.  Winter  Injury  or  Die-Back  of  the  Walnut. 

217.  Methods    for    Marketing    Vegetables    in 

California. 

218.  Advanced  Registry  Testing  of  Dairy  Cows. 

219.  The  Present  Status  of  Alkali. 

220.  Unfermented  Fruit  Juices. 

221.  How  California  is  Helping    People  Own 

Farms  and  Rural  Homes. 


